1. Field of the Invention
The present invention relates to a disc drive apparatus and, in particular, to a reduced-height disc drive apparatus
2. Description of the Related Art
In a conventional hard-disc device, as illustrated in FIG. 1, a hard disc 6 is rotatably held through a spindle motor 4 and a disc fixing hub 5 in a tightly closed box 10 consisting of a housing 3 and a chassis 7.
Proposed on the chassis 7 is a rotary arm 9 rotated about a rotary shaft 8 by means of a linear actuator 16 constructed of a voice coil motor. A rotary position of this rotary arm 9 is detected by, e.g., an opto-positional detector (unillustrated). Recording/reproducing heads 11, 12 attached to the top end of the rotary arm 9 are caused to make a predetermined amount of movement on the surface of the hard disc 6, thereby performing movement-positioning of the recording/reproducing heads 11, 12 with respect to the respective tracks formed in an information recording track region on the hard disc 6.
A linear actuator 16 is constructed such that a yoke member 13 and a tabular magnet 14 are fixed onto the chassis 71, a coil unit 15 fixed to a part of the rotary arm 9 is disposed opposite to the magnet 14; and the rotary arm 6 is rotated by passing a driving current through the coils of the coil unit 15.
The hard disc 6 is placed on the upper surface of a rotary member 4A of the spindle motor 4 and is thereafter fixed to this rotary member 4A of the spindle motor 4 by fixing a disc fixing hub 5 by a method such as screw fastening, etc.
Components consisting of the hard disc, etc. are thus disposed on the chassis 7 and are tightly closed from outside by the housing 3.
A circuit board 17 composed of a glass epoxy material is fixed to a lower surface of the chassis 7. A circuit (not shown) driving the hard-disc device 1 is formed on the surface of the circuit board 17.
This type of hard-disc device 1 is desirably, for the purpose of its being mounted on, e.g., a portable small-sized computer, miniaturized to the greatest possible degree. The thickness dimension thereof, however, to be further decreased.
Hence, in the hard-disc device 1, when the box 10 incorporates the circuit board 17 fixed to the lower surface of the chassis 7, the hard-disc device 1 can be, it is considered, decreased in thickness correspondingly.
Generally, the glass epoxy material for forming the circuit board 17 tends to be contaminated with fine dust. If this glass epoxy material is provided in the box 10, a problem happens i.e., a so-called head crash takes place, wherein foreign matter such as dust enter between the recording/reproducing heads 11, 12 and the hard disc 6.